Pollyanna Santos doesn’t let her 6-year-old son play at a friend’s house unless she knows all of the adults who live in the home — and those who might be visiting. “You don’t know what can happen in the next room,” said Santos, a waitress from East Boston.

In Braintree, Debbie Currie feels anxious when she leaves her 7-year-old daughter at gymnastics class. “There are 20 other kids in there, and we live in a nice town, but you just never know,” said Currie, a customer service supervisor for Comcast.

Bernice Ferrara, a retired MBTA bus driver from Brockton, will not let her 15-month-old granddaughter sit on Santa’s lap because she doesn’t know the man behind the beard. “I don’t want to feel that way,” she said. “But I do.”

After years of revelations about sexual predators lurking in some of our most high-profile institutions, including recent accusations against Elmo’s puppeteer, it has come to this: Parents and caregivers say they’re living in a state of high alert, suspicious of even the most innocuous-seeming encounters, worried even in their own homes, where the Internet has the power to deliver predators to their children’s bedrooms.

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“There is no escaping it,” said Stuart Goldman, a psychiatrist at Boston Children’s Hospital. Among the parents of his patients, he has observed a growing awareness of child sexual abuse, and with it, caution. “Do you feel comfortable having your son camp out in the woods with the Boy Scout leader?” he asked.

AP/File (top); Reuters/File

The list of institutions that have been tarnished by sexual predators has been growing in recent years. Former Penn State University assistant football coach Jerry Sandusky (above) and Kevin Clash, the voice of Elmo, have both been implicated in sexual abuse cases against children. Sandusky was sentenced in October to at least 30 years in prison.

The growing unease about sex abuse is reflected in two surveys taken four years apart by MassKids
, a nonprofit child advocacy organization. In 2003, fewer than half of Massachusetts residents said they would be willing to participate in training to learn about child sexual abuse and how to prevent it. By 2007, two-thirds of residents said they would be willing.

Parental anxiety seems to be on the rise even as the rate of child sexual abuse is falling, according to a large-scale analysis by the Crimes Against Children Research Center at the University of New Hampshire.

Data from the National Child Abuse and Neglect Data System showed that the rate of substantiated child sexual abuse dropped 62 percent between 1992 and 2010, from 150,000 cases to 63,000 cases, said the center’s director, David Finkelhor.

The trend was confirmed by data from six other sources, including governmental agencies, the FBI, and reports by victims, he added.

A combination of factors has led to the decline, said Finkelhor, a UNH sociology professor, including: more aggressive law enforcement; prevention education; public awareness; and cultural changes such as the empowerment of women.

But even so, the list of organizations that have housed molesters keeps growing.

While the Catholic Church has been at the center of sexual abuse scandals for years, the Penn State football program and the Boy Scouts of America have now been implicated.

In early October, Penn State’s former assistant football coach Jerry Sandusky was sentenced to at least 30 years in prison in a child sexual abuse case, and later that month, files were released showing allegations of sexual abuse in the Boy Scouts of America.

“Some of the anxiety is positive, in that people are taking precautions.”

David Finkelhor, UNH Crimes Against Children Research Center

Last month, the Tennis Hall of Fame suspended disgraced star Bob Hewitt following allegations he sexually abused underage girls he coached from the 1970s to the early 1990s, and Kevin Clash, the voice and puppeteer behind the “Sesame Street” character Elmo, resigned after allegations that he had sexual relations with underage boys.

And those are just the nationally known cases. The media regularly carry a steady stream of local stories as well.

In August, Rockport guidance counselor Howard J. Kasper was placed on leave after being accused of inappropriately touching two students years earlier at a school in Beverly.

The media accounts have led to a generalized mistrust among parents that can be seen in the smallest of actions: a father deciding not to run a 10-minute errand and leave his child alone with the piano teacher; a mother watching out the window as a (too friendly?) neighbor plays catch with the kids.

The growing suspicion that predators are among us can be seen in places like Athol, where a 10-year-old “Enough Abuse” training program is gaining a larger audience.

“In the kick-off years we were doing a lot of outreach,” said Rebecca Bialecki, executive director of the nonprofit North Quabbin Community Coalition. “Then we went through a period where there was a lull.”

But within the past few years, “groups are reaching out to us,” Bialecki said.

The training aims to help parents, caregivers, and people who work with children recognize warning signs and keep kids safe, and the message is simple, Bialecki said. “Sexual offenders can look like anyone around you, and they can be in your family, your neighborhood, your friends, and in positions of trust in a community.”

Indeed, 80 percent to 90 percent of abusers are people known to the children, said UNH’s Finkelhor.

Despite the dropping rate of substantiated sexual abuse cases, widespread media coverage and high-profile offenders make for a nervous public, he said. “There’s been a steady parade of sex crimes against children in the news over the last 20 years.”

“Some of the anxiety is positive,” he added, “in that people are taking precautions and thinking about who their kids are with and making sure they’ve talked to their kids, but some of it is probably an overreaction, too.”

Jetta Bernier, executive director of MassKids, says her organization’s surveys show that parents have become more anxious over the years. “In some ways that’s a good thing — there’s greater recognition that this is not just some rare occurrence.”

When the Massachusetts Medical Society asked her to revise a brochure on child sexual abuse that she had written for the group in 2006, Bernier realized she needed to completely re-do it.

“We have learned so much since then,” she said, explaining that in-depth interviews with sexual abusers have provided valuable insight.

Bernier gave an example: “Sometimes [the predator] will start with ‘accidental’ touching to see if the kid is a good target. They’ll sit on the couch really close to the kid and see if he wiggles away. They might even do it in front of another adult. If the kid doesn’t move, that says it’s OK.”

But even as education increases, and abuse rates drop, many parents say the only time they feel truly safe is when their kids are in view.

“Their lives can be destroyed so quickly,” said Christine Nolan, a Somerville mother of three who supervises as many of their activities as possible. “If I can prevent that, I’m going to. They’re all I have.”

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